Sex difference and smoking predisposition in patients with COVID-19

Author: Cai, H., 2020.

The outbreak of novel coronavirus disease 2019 (COVID-19) is quickly turning into a pandemic. Although the disease is now better contained in China, 32 702 cases remain as of March 2, 2020. 10 566 cases and 166 deaths outside of China had been reported as of March 3 (WHO situation report 43), which is a large increase from the 2918 cases and 44 deaths reported on Feb 26 (WHO situation report 37). Rapid progress has been made with diagnostic reagents (eg, nucleic acid detection and detection of IgM or IgG, or both), drug repurposing (eg, remdesivir and chloroquine), and vaccine production. Studies on the biology of viral infection and clinical management of the disease have also been published, some of which have demonstrated that differences in COVID-19 disease prevalence and severity are associated with sex, and smoking is related to higher expression of ACE2 (the receptor for severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]), so that might also be a factor. One study (preprint), using single-cell sequencing, found that expression of ACE2 was more predominant in Asian men, which might be the reason for the higher prevalence of COVID-19 in this subgroup of patients than in women and patients of other ethnicities. One study of 140 patients with COVID-19 in China, found the sex distribution equal; whereas, in a study of critically ill patients, more men were affected (67%) than women. In a latest report of 1099 patients with COVID-19 from 552 hospitals in 30 provinces in China, 58% of the patients were men. Taken together, these data seem to indicate that there might be a sex predisposition to COVID-19, with men more prone to being affected.

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